My first road bike

This is my first post -- and one that I'm sure is asked alot on here -- but I'm unique, darnit ;) I am looking to buy my first road bike and would love some insight.

I have a dutch style bike that I commute to work on (7 miles total) and an old hybrid on it's last leg. I would like to get a road bike that I can take out on the DC area trails for 40-ish mile weekend rides, do charity rides on (maybe someday a century), and possibly use for light "credit-card touring". I don't care to be supper fast -- I'm not looking to be competitive -- just have fun and workout.

I love the look of the steel bikes and would like to go in that direction if it makes sense. I've been doing a lot of looking on the interwebs and hope to get out to bike shops this coming weekend to test a few out. I'd like to buy used if possible, but I'm not sure I know enough to do so well. Any thoughts and advice -- either in general or specific bike recommendations -- would be most certainly appreciated. Thanks!

If you can, go ride a Surly Cross Check and a Surly Long Haul Trucker. Both are super versatile and perfect for what you are describing.

To determine size, the bike hermit has a blog post on measuring your PBH that is super helpful. I smile because a fellow stopped in the other day and said he spent $400 with a bike fitter so out of curiosity the bike hermit measured his PBH and the saddle set up was less than 1/2cm different.